In unconsolidated formations, horizontal and deviated wells are routinely completed with completion systems having integrated sand screens. To control the flow-rate of produced fluids (such as to reduce tubular erosion due to abrasive sand entrained within the produced fluid) the sand screens may use inflow control devices (ICD) to slow fluid rate through the sand screening elements. One ICD example is disclosed in U.S. Pat. No. 5,435,393 to Brekke et al. Other examples of inflow control devices are also available, such as the FloReg™ ICD available from Weatherford International, the Equalizer® ICD available from Baker Hughes, ResFlow™ ICD available from Schlumberger, and the EquiFlow® ICD available from Halliburton. (EQUALIZER is a registered trademark of Baker Hughes Incorporated, and EQUIFLOW is a registered trademark of Halliburton Energy Services, Inc.)
For example, a completion system 10 in FIG. 1 has completion screen joints 50 deployed on a completion string 14 in a borehole 12. Typically, these screen joints 50 are used for horizontal and deviated boreholes passing through a loosely or unconsolidated formation as noted above, and packers 16 or other isolation elements may be used between the various joints 50. During production, fluid produced from the borehole 12 passes through the screen joints 50 and up the completion production string 14 to the surface facility rig 18. The screen joints 50 keep out particulate formation fines, stimulation sand, and other potentially damaging particulates migrating in the produced fluid. In this way, the screen joints 50 can mitigate erosional damage to components, mud caking in the completion system 10, and other problems associated with fines, particulate, and the like present in the produced fluid.
Turning to FIGS. 2A-2C, a prior art completion screen joint 50 is illustrated in side view, partial side cross-sectional view, and in a more detailed cut-away side view. The screen joint 50 may include a basepipe 52 with a sand control screen or jacket 60 and an inflow control device 70 disposed thereon. The basepipe 52 defines a through-bore 55 and has a coupling crossover 56 at one end for connecting to another screen joint, spacer-joint, or the like. The other end 54 can connect to a crossover (not illustrated) of another joint on the completion string. Inside the through-bore 55, the basepipe 52 defines pipe ports 58 where the inflow control device 70 (ICD) is disposed.
The joint 50 is deployed on a production string (14: FIG. 1) with the screen 60 typically mounted so that the screen elements are upstream of the inflow control device 70, but the screen may be positioned structurally above, even with, or below the ICD. Here, the ICD 70 illustrated is somewhat similar to the FloReg™ ICD available from Weatherford International. As illustrated in FIG. 2C, ICD 70 has an outer sleeve 72 disposed about the basepipe 52 at the location of the pipe ports 58. A first end-ring 74 seals to the basepipe 52 with a seal element 75, and a second end-ring 76 engages with the end of the screen 60. Overall, the sleeve 72 defines an annular or inner space 86 around the basepipe 52 communicating the pipe ports 58 with the sand control jacket 60. The second end-ring 76 has flow ports 80, which separates the sleeve's inner space 86 from the screen 60.
For its part, the sand control jacket 60 is disposed around the outside of the basepipe 52. As illustrated, the sand control jacket 60 can be a wire wrapped screen having rods or ribs 64 arranged longitudinally along the basepipe 52 with windings of wire 62 wrapped thereabout to form various slots. Fluid can pass from the surrounding borehole annulus to the annular gap between the sand control jacket 60 and the basepipe 52.
Internally, the inflow control device 70 has nozzles 82 disposed in the flow ports 80. The nozzles 82 restrict flow of screened fluid (i.e., inflow) from the screen jacket 60 to the device's inner space 86 to produce a pressure drop. For example, the inflow control device 70 may have ten nozzles 82, although they all may not be open. Operators may set a number of these nozzles 82 open at the surface to configure the device 70 for use downhole in a given implementation. Depending on the number of open nozzles 82, the device 70 can thereby produce a configurable pressure drop along the screen jacket 60.
To configure the device 70, pins 84 can be selectively placed in the passages of the nozzles 82 to close them off. The pins 84 are typically hammered in place with a tight interference fit and are removed by gripping the pin with a vice grip and hammering on the vice grip. These operations need to be performed off rig beforehand so that valuable rig time is not used up making such adjustments.
When the joints 50 are used in a horizontal or deviated borehole as illustrated in FIG. 1, the inflow control devices 70 help evenly distribute the flow along the completion string 14 and prevent coning of water in the heel section. Overall, the devices 70 choke production to create an even-flowing pressure-drop profile along the length of the horizontal or deviated section of the borehole 12.
Although the inflow control device 70 of the prior art and its arrangement on a completion screen joint 50 is often effective, the prior art completion screen joint 50 such as illustrated in FIGS. 2A-2C has an inflow control device 70 disposed near an end of a sand control jacket 60. Fluid flow through the sand control jacket 60 comes in from only one direction and also tends to be sourced from the sand screen into the flow annulus 64 from the vicinity of greatest pressure drop across the screen, that being in the vicinity of the sand screen nearest the inflow control device 70. More distant portions of the sand screen tend to contribute slower and lesser fluid flow rates to the annulus 64 and ICD 70. Consequently, a majority of the screen jacket 60 may be underutilized.
The more concentrated inflow through the jacket 60 near the device 70 also produces formation fluids less efficiently and can lead to issues with plugging and clogging. This unbalanced flow rate distribution can lead to screen erosion, tool plugging, and other associated problems. However, once a screen jacket 62 becomes compromised with erosional holes, the entirety of the screen becomes virtually useless for its intended purpose. Plugging can also be an issue at any point during operations and may even be problematic when the joint 50 is initially installed in the borehole. For example, the joint 50 may be initially lowered into an unconditioned mud, which can eventually plug the screen 60 and cause well performance and productivity to significantly decline.
Additionally, for vertical, horizontal, and deviated boreholes in an unconsolidated formation, it is beneficial to place stimulation fluids effectively to overcome any near borehole damage and screen plugging that may have developed. Accordingly, a cleanup operation may need to be performed by bullheading a treatment fluid into the well. In bullheading, operators fill a portion of the borehole with treatment fluid (such as an acid system) by pumping the fluid down the tubing string 14 and using fluid pressure to cause the stimulation fluid to flow out of the inflow control device 70 and screen 60, and into the surrounding borehole. Unfortunately, the treatment fluid may be disproportionately forced into the area of the formation near the inflow control device 70 and not into other regions of need. As a result, the concentrated flow and “overstimulation” can cause fluid loss and can over-treat certain areas compared to others. More even and controlled stimulation fluid placement is needed.
The subject matter of the present disclosure is, therefore directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.